Synanthropic rodents as virus reservoirs and transmitters

Abstract This review focuses on reports of hepatitis E virus, hantavirus, rotavirus, coronavirus, and arenavirus in synanthropic rodents (Rattus rattus, Rattus norvegicus, and Mus musculus) within urban environments. Despite their potential impact on human health, relatively few studies have addressed the monitoring of these viruses in rodents. Comprehensive control and preventive activities should include actions such as the elimination or reduction of rat and mouse populations, sanitary education, reduction of shelters for the animals, and restriction of the access of rodents to residences, water, and food supplies.

Rodent-borne viruses survey in rural settlers from Central Brazil

Anthropogenic environmental changes arising from settlement and agriculture include deforestation and replacement of natural vegetation by crops providing opportunities for pathogen spillover from animals to humans. This study aimed to investigate the prevalence of rodent-borne virus infections in seven rural settlements from Midwestern Brazil. Of the 466 individuals tested 12 (2.57%) were reactive for orthohantavirus and 3 (0.64%) for mammarenavirus. These rural settlers lived under unfavorable infrastructure, socioeconomic disadvantages, and unsanitary conditions, representing a risk for rodent-borne infections. Development of public policies towards the improvement of health, sanitation and awareness of rodent-borne diseases in improvised camps and settlements is imperative, in order to reduce morbidity and mortality caused by these diseases.

Conocimientos y prácticas asociadas a transmisión de triquinelosis, hanta y equinococosis quística / Knowledge and practices associated with transmission of trichinellosis, hanta and cystic equinococcosis

RESUMEN Objetivo: Asociar el nivel de conocimiento y prácticas (hábitos y costumbres) responsables de la transmisión de Triquinelosis, Síndrome Cardiopulmonar por Hantavirus y Equinococosis quística (Hidatidosis), en habitantes de los sectores rurales. Material y método: Estudio descriptivo correlacional de corte transversal en el que se aplicó una encuesta a 149 habitantes residentes en el área rural de las localidades de Curacautín, Lonquimay y Melipeuco, a través de muestreo no probabilístico por conveniencia, durante los meses de diciembre 2013 a enero 2014. Resultados: La población posee mejores conocimientos de Triquinelosis y Hanta que Hidatidosis, 64,9, 72,8 y 39,3%, respectivamente; los hábitos y costumbres para Hanta e Hidatidosis alcanzan mejores prácticas (84% cada una) que para Triquinelosis (69,5%); la población reconoce correctamente reservorio, fuente de infección y mecanismos de transmisión en Triquinelosis y Hanta, pero en menor grado Hidatidosis; respecto de los hábitos y costumbres, aun desconociendo los fundamentos teóricos, reportan buenas prácticas, aunque mantienen algunas que favorecen la transmisión de infecciones predominantemente en Triquinelosis. Conclusión: El nivel de conocimiento no asegura buenas prácticas, además los conocimientos y prácticas siguen un patrón empírico más que cognitivo, respaldados por aspectos culturales y del entorno. Esto sugiere mayor participación de los equipos interdisciplinarios en comunidades aisladas para fortalecer la promoción, educación y refuerzo de las buenas prácticas de acuerdo con sus condiciones sociales e incentivar la adherencia a conductas que reduzcan el riesgo de la transmisión de zoonosis.

ABSTRACT Objective: To associate the level of knowledge and practices (habits and customs) responsible for the transmission of trichinellosis, Hanta and cystic echinococcosis (hydatidosis), among rural population. Material and method: Cross-sectional correlational descriptive study in which 149 residents of the rural areas of Curacautín, Lonquimay and Melipeuco were surveyed, using non-probability convenience sampling from December 2013 to January 2014. Results: The population has better knowledge of trichinellosis and Hanta than hydatidosis, 64.9%, 72.8 and 39.3% respectively; they also have better practices regarding Hanta and hydatidosis (84% each) than regarding trichinellosis (69.5%). The population recognizes correctly the reservoir, source of infection and transmission mechanisms of trichinellosis and Hanta, and to a lesser degree hydatidosis; they report good practices regarding habits and customs, even ignoring theoretical foundations, but maintain some practices that favor the transmission of infections related to trichinellosis. Conclusion: The level of knowledge does not ensure good practices. Additionally, knowledge and practices follow an empirical rather than cognitive pattern, rooted on cultural and environmental aspects. This suggests greater participation of interdisciplinary teams in isolated communities to strengthen the promotion, education and reinforcement of good practices in accordance with their social conditions and to encourage adherence to behaviors that reduce the risk of the transmission of zoonoses.

Ten years of a hantavirus disease emergency in the Federal District, Brazil

Abstract: INTRODUCTION: Hantavirus diseases are emerging human diseases caused by Hantavirus spp. of the Bunnyaviridae family. Hantavirus pulmonary syndrome (HPS) has been detected in the Federal District (DF) of Brazil since 2004. Among the 27 Brazilian Federal Units, DF has the highest fatality rate. More than 10 years have already passed since then, with confirmation of cases caused by the Araraquara and Paranoa species. The reservoir is Necromys lasiurus. METHODS: Local surveillance data of the confirmed cases were analyzed, including age, sex, month and year of occurrence, clinical symptoms, syndromes and outcomes, and probable transmission place (PTP). The cases were mainly confirmed by IgM detection with a capture enzyme immunoassay. The cases were classified as autochthonous if PTPs were in the DF area. RESULTS: From 2004 to 2013, in the DF, 126 cases of hantavirus were confirmed, and the cumulative incidence was 5.0 per 100,000 inhabitants. The occurrence of cases was predominantly from April to August. At least 75% of the cases were autochthonous. Acute respiratory failure was reported in 47.5% of cases, and the fatality rate was 40%. CONCLUSIONS: In the DF, the cumulative incidence of HPS was one of the highest worldwide. A seasonal pattern of hantavirus disease in the dry season is clear. There was a high frequency of severe clinical signals and symptoms as well as a high fatality rate. For the near future, visitors and inhabitants of DF rural areas, particularly male adults, should receive continuous education about hantavirus transmission and prevention.

Soroprevalência de Bartonella sp., Coxiella burnetii e Hantavirus em Pessoas que Injetam Drogas Ilícitas no Estado do Rio de Janeiro nos anos de 1999 a 2001 / Seroprevalence of bartonella sp., coxiella burnetti and hantavirus in intravenous illicit drug users in the state of Rio de Janeiro in the years of 1999-2001

O aumento do consumo de drogas ilícitas na atualidade vem acompanhado não apenas do impacto social e econômico, como também na saúde. As pessoas que injetam drogas apresentam maior susceptibilidade a infecções por diversos agentes, devido ao uso da droga e à subsequente imunossupressão, como também pelo risco de maior exposição a agentes transmitidos por artrópodes e reservatórios vertebrados em ambientes insalubres. São muitos os estudos correlacionando o consumo de drogas à infecção pelo HIV, VHB e VHC, porém raros investigam outros agentes. No presente estudo transversal e retrospectivo, selecionamos aleatoriamente 300 amostras de um estudo multicêntrico da década de 1990 e fizemos a pesquisa sorológica para Bartonella spp., Coxiella burnetii e Hantavirus. O perfil demográfico e social encontrado mostrou-se em concordância com a literatura: homens, jovens, de baixa renda e com histórico de prisão. A maior parte apresentava situações de risco por injetar drogas com dispositivos previamente usados e por injetar em local público. Alguns fatores foram discordantes da literatura internacional e podem ter influenciado os resultados, uma vez que são considerados situações de risco, como escassez de pessoas que injetaram drogas enquanto presas, que residem em instituições, ou sem-tetoA evidência de infecção por C. burnetii foi de 9,3 porcento, praticamente o dobro da observada na população geral brasileira, embora, em comparação com dados internacionais, a prevalência tenha sido menor. Não houve diferença estatística significativa em relação às variáveis demográficas entre os grupos sororeativos e soronegativos para febre Q. A presença de anticorpos anti-Bartonella foi de 1 porcento, bem discrepante dos estudos nacionais e internacionais. Pode ser justificado pela não inclusão no teste sorológico de antígeno de B. elizabethae e de B. quintana e pela reduzida frequência de sem-tetos...

The increased consumption of illicit drugs today is followed not only by a social and economic impact, as well as in health. People who inject drugs are more susceptible to infections by various agents due to drug use and subsequent immunosuppression, as well as the risk of increased exposure to agents transmitted by arthropods and vertebrate reservoirs in unhealthy environments. Many studies link drug use to HIV, HBV and HCV,however only a few investigate other agents. In this retrospective cross-sectional study, we selected randomly 300 samples from a multicenter study from the 1990s and made aserological survey for Bartonella spp., Coxiella burnetii and hantavirus. The demographic and social profile was found in agreement with the literature: men, young age, low incomeand with a history of imprisonment. The majority was exposed to risk situations by injecting drugs with previously used devices and by injecting in a public places. Some factors were disagreeing with the international literature and may have influenced theresults, since they are considered high-risk situations, such as shortage of people whoinjected drugs while imprisoned, residing in institutions, or homeless. Evidence of C.burnetii infection was 9.3 percent, almost double the rate in the general Brazilian population,although in comparison with international data, the prevalence was lower. There was nostatistically significant difference in relation to demographic variables among seroreactiveand seronegative groups for fever Q. The presence of antibodies to Bartonella was 1percent, significantly discrepant from national/international studies. Possibly justified by the noninclusion of antigen B. elizabethae and B. quintana in the serological test, and the reduced frequency of homelessness. There was no correlation between high alcohol consumption with higher seroprevalence of Bartonella spp., probably for the reasons mentioned above...

Serological survey of hantavirus in rodents in Uberlândia, Minas Gerais, Brazil / Inquérito sorológico de hantavírus em roedores, Uberlândia, Minas Gerais, Brasil

We conducted a serological survey to determine the presence of hantavirus infection in rodents in Uberlândia, Minas Gerais as well as to identify and characterize associated factors. Rodents were captured using Sherman live-capture traps set in rural and peri-urban environments. A total of 611 rodents were captured. There was a higher trap success in peri-urban areas (26.3%) and a higher prevalence of antibodies among rodents captured in rural areas (2.9%). Necromys lasiurus was the most common species (42.2%) and the more frequently infected (4.6%). One Calomys tener (1/141; 0.7%) and one Calomys sp. (1/14; 7.1%) were also positive for the hantavirus infection. In N. lasiurus, antibody prevalence correlated with population density (p < 0.01), age class (p = 0.003) and presence of scars (p = 0.02). The data confirm that horizontal transmission is the main mechanism that maintains the virus in nature. The higher seropositivity in N. lasiurus is consistent with genetic studies that associate this species with an Araraquara virus reservoir; the seropositivity of C. tener and Calomys sp. may indicate the occurrence of spillover infection or the presence of other circulating hantaviruses.

Realizamos um estudo transversal para identificar a presença de infecção por hantavírus em roedores em Uberlândia, Minas Gerais, e também para identificar e caracterizar fatores associados. Roedores foram capturados usando armadilhas do tipo Sherman em ambientes rural e periurbano. Um total de 611 roedores foi capturado. Houve maior sucesso de captura na área periurbana (26,3%) e maior prevalência de anticorpos entre os roedores capturados na área rural (2,9%). Necromys lasiurus foi a espécie mais encontrada (42,2%) e a mais frequentemente infectada (4,6%). Um Calomys tener (1/141; 0.7%) e um Calomys sp. (1/14; 7.1%) foram também positivos. Os dados obtidos mostram que em N. lasiurus, a prevalência de anticorpos está relacionada à densidade populacional (p < 0.01), a classe de idade (p = 0.003) e a presença de cicatrizes (p = 0.02), confirmando que a transmissão horizontal é o principal mecanismo que mantém o vírus na natureza. A maior positividade em N. lasiurus é consistente com estudos genéticos que permitem associar esta espécie como reservatório do vírus Araraquara; a soropositividade de C. tener e Calomys sp. pode indicar a ocorrência de "spillover infection" ou a presença de outros hantavírus circulantes.

Barn owl (Tyto alba) predation on small mammals and its role in the control of hantavirus natural reservoirs in a periurban area in southeastern Brazil / Predação de pequenos mamíferos por suindara (Tyto alba) e seu papel no controle de reservatórios naturais de hantavírus em uma área periurbana no Sudeste do Brasil

The aim of this study was to inventory the species of small mammals in Uberlândia, Minas Gerais, Brazil, based on regurgitated pellets of the barn owl and to compare the frequency of rodent species in the diet and in the environment. Since in the region there is a high incidence of hantavirus infection, we also evaluate the importance of the barn owl in the control of rodents that transmit the hantavirus. Data on richness and relative abundance of rodents in the municipality were provided by the Centro de Controle de Zoonoses, from three half-yearly samplings with live traps. In total, 736 food items were found from the analysis of 214 pellets and fragments. Mammals corresponded to 86.0 percent of food items and were represented by one species of marsupial (Gracilinanus agilis) and seven species of rodents, with Calomys tener (70.9 percent) and Necromys lasiurus (6.7 percent) being the most frequent. The proportion of rodent species in barn owl pellets differed from that observed in trap samplings, with Calomys expulsus, C. tener and Oligoryzomys nigripes being consumed more frequently than expected. Although restricted to a single place and based on few individuals, the present study allowed the inventory of eight species of small mammals in Uberlândia. The comparison of the relative frequencies of rodent species in the diet and in the environment indicated selectivity. The second most preyed upon species was N. lasiurus, the main hantavirus reservoir in the Cerrado biome. In this way, the barn owl might play an important role in the control of this rodent in the region, contributing to the avoidance of a higher number of cases of hantavirus infection.

O objetivo deste estudo foi inventariar as espécies de pequenos mamíferos em Uberlândia, Minas Gerais, Brasil, com base em pelotas regurgitadas de suindara e comparar a freqüência das espécies de roedores na dieta e no ambiente. Como na região ocorre grande incidência de casos de hantavirose, também se avaliou a importância da suindara no controle de roedores que transmitem o hantavírus. Os dados de riqueza e abundância relativa de roedores no município foram fornecidos pelo Centro de Controle de Zoonoses, a partir de três amostragens semestrais com armadilhas. No total, foram encontrados 736 itens alimentares a partir da análise de 214 pelotas e fragmentos de regurgitação. Os mamíferos corresponderam a 86,0 por cento dos itens alimentares e estiveram representados por uma espécie de marsupial (Gracilinanus agilis) e sete espécies de roedores, sendo os mais freqüentes Calomys tener (70,9 por cento) e Necromys lasiurus (6,7 por cento). A proporção das espécies de roedores nas pelotas da suindara diferiu daquela observada nas coletas com armadilhas, sendo que as espécies Calomys expulsus, C. tener e Oligoryzomys nigripes foram consumidas com maior freqüência do que o esperado. Apesar de restrito a um único local e baseado em poucos indivíduos, o presente estudo permitiu inventariar oito espécies de pequenos mamíferos em Uberlândia. A comparação da freqüência relativa das espécies de roedores na dieta e no ambiente indicou a existência de seletividade. A segunda espécie mais predada foi N. lasiurus, o principal reservatório de hantavírus no bioma Cerrado. Desta forma, a suindara parece desempenhar um importante papel no controle desse roedor na região, contribuindo para evitar um maior número de casos de hantavirose.

Aspectos climáticos em áreas de transmissão de hantavirose no Estado de São Paulo, Brasil / Climatic aspects in hantavirus transmission areas in São Paulo State, Brazil

O objetivo deste trabalho foi investigar a distribuição espacial dos casos notificados de hantavirose (n = 80) no Estado de São Paulo, Brasil, de 1993 a 2005, e identificar os padrões climáticos locais nos anos de registro da doença. Foi utilizado o estimador de densidade de pontos de kernel que apontou maior concentração nas regiões de Ribeirão Preto, São Carlos, Franca, Tupi Paulista e Grande São Paulo. O aumento do número de casos no período sugere disseminação da doença, embora se considere o aumento da capacidade diagnóstica e maior sensibilidade do sistema de saúde. Registrou-se marcada sazonalidade da hantavirose nas áreas de cerrado, com padrão comum, isto é, maior incidência em meses com baixa pluviosidade, comparados com médias dos últimos quarenta anos. Esses períodos coincidem com épocas de maior disponibilidade de alimentos a roedores em cultura de grãos, cana e outros. A colheita e armazenamento desses grãos aumentam a exposição de populações humanas aos roedores. Indicadores climáticos em conjunto com variáveis ecológicas podem compor marcadores de risco de transmissão local a serem valorizados nas ações de vigilância epidemiológica e controle da doença.

The objective of this study was to investigate the spatial distribution of reported hantavirus cases in São Paulo State, Brazil (n = 80), from 1993 to 2005 and identify local climatic patterns during this period. Kernel point estimation of density was used to show the highest concentrations in Ribeirão Preto, São Carlos, Franca, Tupi Paulista, and Greater São Paulo. Increase in the number of cases during this period suggests disease dissemination even when considering increased diagnostic capacity and higher sensitivity of the health services. There was a marked seasonal variation in hantavirus in the cerrado (savannah) areas; the common pattern is a higher incidence in drier months as compared to mean levels in the last 40 years. These coincide with periods of high rodent food source levels in grains, sugarcane, and other crops. Harvesting and storing grains increases human exposure to rodents. Climatic indicators together with ecological variables can be local transmission risk markers and should receive more attention in epidemiological monitoring and control of the disease.

El desafío de las enfermedades emergentes y reemergentes / The challenge of emerging and re-emerging diseases

En los albores del siglo XXI, las enfermedades emergentes o reemergentes plantean un serio desafío para su control. Las enfermedades emergentes son enfermedades infecciosas con incidencia en aumento en las últimas dos décadas. Se identifican con diversas etiologías: priónica, viral, bacteriana, micótica o parasitaria; en diferentes poblaciones de riesgo, con diferentes vías de transmisión, historia natural y eco epidemiología. Como reemergentes figuran aquellas afecciones infecciosas conocidas que reaparecen después de una disminución significativa de su incidencia. Para controlar estos preocupantes fenómenos, se debe interpretar a estas dolencias infecciosas dentro de una ecología tanto global como local con carácter dinámico, pues están moduladas por cambios tecnológicos, sociales, económicos, ambientales y demográficos, a lo que se suma el potencial de cambio y capacidad de adaptación de los microorganismos. El desafío requiere una estrategia integrada, que contemple el fortalecimiento de la vigilancia epidemiológica y del laboratorio, con alto nivel científico, así como la construcción de infraestructura internacional y local capaz de responder con soluciones adecuadas y oportunas. Es imprescindible el desarrollo de estrategias de prevención y control de las enfermedades emergentes, por medio de intervenciones eficaces basadas en investigaciones prácticas y realistas. El objetivo de esta revisión no exhaustiva sobre el tema es encarar las generalidades de estas infecciones, profundizando en algunos ejemplos seleccionados